IPTV (Internet Protocol Television) is a technology for broadcasting television signals using the Internet Protocol over consumer broadband connections such as digital subscriber line (DSL) lines. IPTV refers to both live TV (multicasting) as well as stored video (Video on Demand VOD). Fundamentally, the DSL physical layer for IPTV is the same as the one for providing high-speed Internet. In practice, the required performance objectives are significantly different between IPTV and high-speed Internet. Therefore, DSL diagnostic tools designed for a high-speed Internet service may not be adequate for an IPTV service. For example, a small number of errors in the physical layer may not be noticed by the web-surfer, but may result in unsatisfactory experience for the IPTV viewer. In contrast, when errors occur while web-surfing, the lost packets can in most cases be received through retransmission without the customer perceiving the errors. However, for IPTV, once an uncorrectable error occurs, the customer will immediately notice it.
Content providers using video streaming, such as IPTV providers, maintain their applications independent from the DSL service provider. As a result, the DSL service provider typically does not diagnose problems above the physical layer. In contrast, content providers maintain their own applications and typically do not diagnose problems at the physical layer. The physical layer is one of the seven abstract layers defined in the Open Systems Interconnection Basic Reference Model (OSI). The seven layers are commonly known as the physical, link, network, transport, session, presentation and application layers. However, video streaming errors may arise from more than one of the seven layers. Previous solutions to this problem either ignore the availability of data from more than one layer, which can often lead to unreliable IPTV service.